I have service from ATT Fiber 300mbps service. When doing a speed test at the modem provided by ATT I get 300 Mbps up and down. From the Modem I have it going to a router D-links DIR-655 which has a gigabit WAN + 4 Gigabit lan ports. When I test a network cable from the router to a laptop with a cat 5e cable I am getting only 256mbps down and 145 Mbps up . I have setup the router WAN at 1000 Mbps in the d-links software. I don't know what can be causing the issue. The wires in the home are Cat5e. I am needing network expert help to understand what it could be. Also from the router i have a 24 port gigabit switch that distributes the signal though out the house and them in some rooms I have 4 or 8 port switches to hook multiple devices. I am testing the speed directing at the att modem and the router. So I don't understand how there can be such a large gap in speed between the ATT Modem and the home router. I turned off the WiFi radio portion in the D-Links router since I use Google mesh in my home. I read he Google mesh devices can output up to 1000 mbps. So I don't think that Google devices is the issue. Any expert advice and help is most appreciated.